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Citrus Black Spot

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Citrus black spot is a fungal disease that leaves fruit speckled and lesioned but does

not affect the internal quality of the infected fruit. Many citrus species are at risk for

citrus black spot, making strict regulation and management necessary to prevent

the spread of this disease.
Citrus black spot is caused by the fungus Phyllosticta citricarpa. It is spread through

leaf litter, from fruit to fruit and leaves through rain splash, and through humanassisted movement.

When trees are severely infected, fruit may drop prematurely, resulting in significant

yield loss. The disease was first identified in the United States in 2010 in Florida.

What To Look For

Symptoms can be found on fruit and leaves. They are are easiest to identify during

"color break," when fruit turns from green to ripe coloration. Here's what to look for:

Lesions on leaves

Young lesions are small, round, slightly raised, reddish-brown with light

centers and a diffuse yellow halo. Older lesions are sunken, with a gray

center and dark brown margin.

Lesions on fruit are diverse and grouped by symptom-based names.

Hard spot lesions

This is the most typical symptom of citrus black spot on fruits. They

appear as the fruit matures, often around the time of color change. Look

for as circular depressions that are 3 to 10 millimeters in diameter. Lesions

have tan to gray centers with a distinct or prominent brick-red to dark

brown margin. They develop on the side of the fruit most exposed to

sunlight.

False melanose

Symptoms appear as numerous, small lesions that are dark brown, raised,

and less than 1 millimeter (0.04 inch) in diameter. These lesions are much

smaller than hard spot lesions. False melanose occurs on green fruit.

Freckle spot

These lesions are round depressions that are 1 to 3 millimeters (0.04-0.12

inches) in diameter and reddish in color. This type of symptom is

considered a sign of a heavy infection. Freckle spot lesions can remain as

single lesions or fuse into the virulent spot type of lesion late in the season

or during storage.

Cracked spot
These lesions are dark, smooth, and variable in size with irregular margins

and a cracked surface. They form on green fruit and remain visible on

mature fruit. This symptom has only been observed in the Americas and is

often found associated with rust mite damage.

Virulent spot

These lesions occur on heavily infected mature fruit toward the end of the

growing season. They are discolored, sunken, and irregular lesions that

cover a large area of the fruit. This symptom is caused by the expansion

and/or fusion of other lesions. Virulent spot may accompany premature

fruit drop and serious postharvest damage because the lesions may

extend into the fleshy part of the fruit.

View images of citrus black spot.

How To Prevent This Disease

Know the quarantines in your area.

Buy only USDA-certified citrus plants.

Don't move branches, green waste, dead trees, and other regulated items out

of a quarantined area.

Don't mail or transport home-grown citrus fruit or plants out of a quarantined

area.

Commercial nurseries must follow strict protocols for moving citrus nursery

stock out of quarantined areas.

Report Signs of Citrus Disease

If you think you've seen signs of this disease or pest, immediately report it by

completing our online form.

Report Form (English)

Report Form (Spanish)

Controlling Citrus Black Spot

Current Status
At this moment, citrus black spot is only found in southern Florida.

Table of Federal Quarantine Descriptions

Interactive Citrus Federal Quarantine Map

Regulatory Information

The regulated articles below can move interstate from a quarantine area if certain

conditions in the Federal Order are met.

- Fruit of Citrus spp.

- All plants and plant parts, including but not limited to leaves for consumption,

budwood, and nursery stock of Citrus spp.

- Other articles intended for consumption, as apparel or as a similar personal

accessory, or decorative use made from Citrus spp.

- Any other products, articles, or means of conveyance of any character whatsoever,

when it is determined by an inspector that they present a hazard of spread of CBS

and the person in possession thereof has been provided notice.

Regulated Articles Table

APHIS-Approved Packinghouse Procedures for Citrus Black Spot

Potentially Actionable Suspect Sample Policy

A potentially actionable suspect sample (PASS) is a regulatory sample3 from the

environment or an APHIS-approved exclusionary facility5 where preliminary

diagnostics indicate that Phyllosticta citricarpa, a USDA regulated pathogen, is

present and must be confirmed by APHIS' Plant Pathogen Confirmatory Diagnostics

Laboratory (PPCDL).

Samples Collected from a Non-Regulated Area

Any regulatory sample collected from a non-regulated area1 or APHISapproved exclusionary facility that tests positive using APHIS-approved tests for

the presence of Phyllosticta citricarpa, the causative agent for citrus black spot, is

considered a PASS and must be forwarded to PPCDL for final determination. A
sample 4 should consist of symptomatic plant material (fruit or leaves).

Sample Diagnostics

USDA APHIS PPQ Science & Technology

Plant Pathogen Confirmatory Diagnostics Laboratory

9901 Powder Mill Rd. Bldg. 580

Laurel, MD 20708

Phone: (301) 313-9208 or (301) 313-9271

When forwarding materials, notify the lab by email (APHISPPQCPHSTBeltsvilleSampleDiagnostics@usda.gov). Include the number of samples,

screening diagnostic results, and tracking information in this communication. Do not

ship samples on Fridays or the day before a federal holiday.

Please see additional information for preparing and submitting samples.

Samples Collected from a Regulated Area

A regulatory sample collected in a regulated area2 where preliminary

diagnostics indicate Phyllosticta citricarpa is considered a PASS and requires

confirmation by PPCDL ONLY under the following conditions:

The sample is an unusual detection (novel symptoms or new host), and/or

The sample will result in the expansion of a previously established regulated

area

If neither of these conditions apply, the sample should be evaluated by the Statedesignated laboratory for final determination.

Definitions

1 Non-Regulated Area: Any area where citrus black spot is not known to occur in

the United States.

2 Regulated Area: Any APHIS-recognized area where citrus black spot has been

federally confirmed.

3 Regulatory Sample: This is a sample of regulatory concern to APHIS for citrus

black spot collected by regulatory officials.
4 Sample: A sample refers to a fruit or single bag of leaves (5 to 12 symptomatic

leaves). It is strongly encouraged that each sample (fruit or leaf) is from a single

plant.

5 APHIS-approved exclusionary facility: A greenhouse structure designed to

exclude quarantine pests that is approved by APHIS to produce citrus nursey stock

for interstate movement.